What is move constructor and move assignment?

Question

Accepted Answer

**Move constructor/assignment** — transfer resources from one object to another, avoiding deep copies.

```cpp
class Buffer {
    size_t size;
    char* data;
public:
    Buffer(size_t s) : size(s), data(new char[s]) {}
    ~Buffer() { delete[] data; }

// Move constructor
    Buffer(Buffer&& other) noexcept
        : size(other.size), data(other.data) {
        other.size = 0;
        other.data = nullptr;
    }

// Move assignment
    Buffer& operator=(Buffer&& other) noexcept {
        if (this != &other) {
            delete[] data;
            size = other.size;
            data = other.data;
            other.size = 0;
            other.data = nullptr;
        }
        return *this;
    }
};

Buffer a(1024);
Buffer b = std::move(a);  // Move, no allocation!
```

**Rules:**
- Mark as noexcept for STL container optimizations.
- Leave source in a valid but unspecified state.
- Handle self-assignment.

C++: What is move constructor and move assignment?